Winding machine with support cylinders

ABSTRACT

For winding webs of material on cores winding machines have two support rollers on which the winding rolls are supported during winding. The web is guided from underneath through the gap between the support cylinders. When the winding rolls are exchanged, for the cutting of the web a cutting knife with a tear-off blade is raised through the gap between the support cylinders up to the cylinder bed. In order to reduce the bearing load of the winding rolls on the support cylinders in the lower wedge between the two support cylinders an air box extending over the work width and having a compressed air supply line is provided, which seals the gap between the support cylinders and has an air exit slot open towards this gap. The tear-off blade of the cutting knife is attached to a support arranged in the air box and can be moved up and down through the air exit slot into the cutting position in the cylinder bed and completely lowered into the air box.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national phase of PCT/EP 93/00965 filed 21 Apr.1993 and based, in turn, on German national application P 42 19 541.1 of15 Jun. 1992 under the International Convention.

FIELD OF THE INVENTION

Our present invention relates to a winding machine with supportcylinders for winding webs of material, particularly paper or cardboardwebs on cores. Such winding machines serve for the manufacture of woundrolls from webs of material subdivided through longitudinal sectioning.During winding the winding rolls are supported in axial, alignment onthe two support cylinders.

BACKGROUND OF THE INVENTION

In order to keep the standstill times of a winding machine as short aspossible during the exchange of the winding rolls, it is known fromDE-OS 2920707 to cut the web of material in the cylinder bed formed bythe support cylinders by means of a sectioning device having a tear-offblade, which can be raised through the gap between the cylinders, at themoment when the fully wound roll is pushed off. The new web end createdby the cut is kept by underpressure (suction) on the wrapped supportcylinder, until a new set of cores is introduced onto the cylinder bed,i.e. the gap formed between the support cylinders.

From WO 92/03366 a winding machine with support cylinders is known,wherein superatmospheric pressure is created with compressed air in thespace defined by the support cylinders and the winding rolls. Thissuperatmospheric pressure reduces the bearing load and thereby also theline load (=bearing load per width of a winding roller) at the twocontact lines of each wound roll on the support cylinders, which has asignificant influence on the winding firmness of the winding roll.Because of this load reduction, it is possible to wind winding rollswith very large diameters (more than 800 mm) with very good windingquality.

According to one embodiment, in the area of the lower wedge between thesupport cylinders an air box is provided. The air box extends over theentire work width (=axial length of the support cylinders) and isprovided with a supply line for compressed air. The air box is swingablefrom an upper work position, wherein its lateral surfaces are pressedsealingly against the support cylinders to a position underneath onesupport cylinder. The lowering makes room for a separate cutting knifewhich can be raised from below through the gap between the supportcylinders and whose tear-off blade tears off the web when the fullywound roller is pushed out.

OBJECT OF THE INVENTION

It is the object of the invention to provide an improved winding machinewith support cylinders, so that it has a compact construction and ispossible to perform the roll replacement in a shorter time.

SUMMARY OF THE INVENTION

This object is achieved in a winding machine with support cylinders forwinding a web of material, particularly a paper or cardboard web, ontocores with two support cylinders on which the winding rolls aresupported during winding, whereby the web of material partially loopedaround a support cylinder is guided from underneath through the gapbetween the support cylinders. A cutting knife for sectioning the webwhen the winding rolls are replaced has a tear-off blade which can belifted through the gap between the support cylinders until it reachesthe cylinder bed. An air box extends over the working width and has acompressed air supply line and is arranged in the lower wedge betweenthe support cylinder to seal the gap between the support cylinders,being provided with an air exit slot extending over the work width.

According to the invention the tear-off blade of the cutting knife isfastened to a support which can move up and down in the air box and canbe raised through the air exit slot until it reaches its cuttingposition in the cylinder bed and can be completely lowered into the airbox.

The arrangement of the cutting knife support with the tear-off blade inthe air box requires less space than a separate cutting knife.Furthermore, the air box does not have to be lowered in order to replacethe rolls. Its lowering is required only when a new web is inserted orin case of a paper jam. The roll exchange can be done quickly, becausethe tear-off blade can be raised to its cutting position in the cylinderbed, without having first to swing away the air box.

The arrangement of the cutting knife support with the tear-off blade inthe air box requires less space than a separate cutting knife.Furthermore, the air box does not have to be lowered in order to replacethe rolls. Its lowering is required only when a new web is inserted orin case of a paper jam. The roll exchange can be done quickly, becausethe tear-off blade can be raised to its cutting position in the cylinderbed, without having first to swing away the air box.

The tear-off blade can be fastened to a holder which is supported on thesupport so that it can be swung towards the wrapped cylinder.

The holder of the tear-off blade can be a two-part lever, whose sideturned away from the tear-off blade is connected with a piston-cylinderunit fastened to the lower part of the support.

The piston-cylinder unit can be linked to a lever which is articulatelymounted to the holder, whereby its link point is slightly offset in thedirection of the support cylinder which is not looped by the web, whenthe piston rods are retracted.

On the end of the holder facing away from the tear-off blade, freelyrotatable wheels are mounted and in the upper part of the air boxvertical guides for the wheels are arranged.

In the air box a piston-cylinder unit is mounted for the up and downmovements of the support, whereby at least its piston rod is locatedinside the air box.

BRIEF DESCRIPTION OF THE DRAWING

The drawing serves for the clarification of the invention with respectto an embodiment of the winding machine. In the drawing:

FIG. 1 is a schematic lateral view in section of a winding machine withsupport cylinders;

FIG. 2 is an enlarged representation in cross section through the airbox with the cutting knife in rest position; and

FIG. 3 is a cross section wherein the tear-off blade of the cuttingknife is in the sectioning position.

SPECIFIC DESCRIPTION

The winding machine with support cylinders has two driven supportcylinders 1, 2, between which a cylinder bed is created. In the cylinderbed the winding rolls 4 rest on the support cylinders 1, 2 duringwinding. The web of material 5, preferably a paper or cardboard web,longitudinally subdivided in individual webs is guided by supportcylinder 1 and directed from underneath through the gap between supportcylinders 1, 2 into the support cylinder bed 3 and there wound ontocores 6 aligned in a row. The finished wound rolls 4 are pressed by anejection bar not shown in the drawing over the support cylinder 2 onto alowering platform 7, from where the wound rolls 4 are lowered fordischarge.

In order to reduce the bearing load of the winding rolls 4 on thesupport cylinders 1, 2, in the space defined by the support cylinders 1,2 and the winding cores 6, (i.e. in the upper wedge-shaped gap 0)overpressure can be created with compressed air. For this purpose in thelower wedge between the two support cylinders 1, 2 an air box 8 with asupply line 9 for compressed air is provided, which extends over theaxial length of the support cylinders 1, 2 and whose lateral surfacesfacing the support cylinders 1, 2 are curved in their upper portion tofit the peripheral surfaces of the support cylinders 1, 2, so that theycan snugly seal them.

In the curved lateral surfaces, several axially extending felt stripsare laid on the outside, which at minimal friction seal the air box 8with regard to the support cylinders 1, 2. The air box 8 is mounted onpivot arms 10 which are supported in the machine stand. In this way theair box 8 can be lowered from its upper sealing position until itreaches a rest position shown in FIG. 1 in dash-dot lines, e.g. in orderto introduce a new web 5. In its upper sealing position, its upperportion of the air box reaches up to the narrowest area between the twosupport cylinders 1, 2. The upper limiting surface facing the supportcylinder gap has an air exit slot 11 extending at least over the minimalweb width and is designed on both sides of the machine to serve as guidesurfaces for two frontal sealing elements 12 arranged on both sides ofthe machine.

The shape of the frontal sealing elements 12 is fitted to the shape ofthe free cross section surface between the support cylinders 1, 2,whereby its upper portion is rectangularly extended beyond theconnection line between the two apexes of the support cylinders 1, 2, sothat in the case of winding rolls 4 with large diameter a sufficientsealing surface is insured. The sealing elements 12 are movable in axialdirection--i.e. transversely to web 5--fastened slidably to lateralpivot arms 13, whose pivot axis runs slightly eccentrically andoutwardly offset on the connection line between the two supportcylinders. In way the sealing elements 12 can be swung out of thecylinder bed 3, over the support cylinder 2 into a position in which itis possible to introduce lateral guide heads into the cores 6. The veryslight eccentricity leads to the fact that the lateral surfaces of thesealing elements 12 facing the support cylinders 1, 2, when swungoutwardly, move away slightly from the respective support cylindersurface, e.g. making possible the removal of paper scraps.

In the air box 8 a cutting knife 14 with a tear-off blade 15 isarranged, which in the sealing position of the air box 8 moves upwardlyreaching the cylinder bed 3 and which can be lowered into the air box 8.In FIG. 2 the tear-off blade 15 is lowered, in FIG. 3 it is in itscutting position in the cylinder bed 3.

The tear-off blade 15 extends over the entire length of the feedingslot, i.e. basically over the entire machine width. It is fastened tothe end of a holder 16 also extending over the machine width and havingthe shape of a two-part lever, which is linked approximately centrallyto the end of a vertical support 18 and is rotatable about an axis 17parallel to the axes of the support cylinders.

The support 18 is fastened to the end of piston rods 19 of vertical,hydraulic piston-cylinder units, whose cylinders 20 are bolted tightlyto the bottom of the air box 8 and are supported by it. To the lower endof the support 18, the cylinders 21 of pneumatic piston-cylinder unitswhose piston rods 22 extend vertically upwards, are fastened. The end ofpiston rods 22 are articulately connected with the holder via lever 23in such a manner that the linkage points 24 with the holder 16, when thepiston rods 22 are completely retracted, are slightly offset in thedirection of the support cylinder 2 with respect to the linkage points25 with the piston rods 22.

The tear-off blade 15 is moved in the direction of the support cylinder1 when the piston rods 22 are extended, as shown in FIG. 3. In order tobe able to stretch the holder 16 and the lever 23, the support 18 has inits upper part recesses for receiving the same. The end of lever 23facing away from the tear-off blade 15 consists of separate strapsarranged at a distance from each other, whereby on the end of each strapalternately either one of the levers 23 is linked or a freely rotatablewheel 26 is supported. The axis of rotation of the freely rotatablewheels 26 runs coaxially with the link points 24. There are alsorecesses provided in the upper part of support 18 for these wheels 26axially offset in the direction of the levers 23, wherein they can move.

The lower part of the support 18 with the piston cylinder units 21, 22is guided along vertical guides 27, which are arranged in the upper partof the air box 8. On the side towards support cylinder 2, offset inaxial direction with respect to the guides 27, further vertical guiderails for the wheels 26 are fastened to the upper part of air box 8,these determining the tilted position of the holder 16, while the wheels26 are still in the air box. As soon as the wheels 26 leave the air box8 travelling upwards, they are guided by the support cylinder 2, thisway establishing the tilting position of holder 16 with the tear-offblade 15.

In the embodiment described the entire cutting knife with its liftingmechanism is arranged in the air box 8. It is also possible to fastenthe cylinder 20 of the piston-cylinder unit 19, 20 outside on the bottomof the air box 8 and to guide the piston rod 19 sealed through thebottom of the air box 8. This has the advantage that the supply linesfor the piston-cylinder unit 19, 20 can be arranged outside the air box8. If for the stability of the air box 8 it is necessary to arrangetransverse partitions, the cutting knife 14 can be subdivided intoseparate segments (e.g. four in a work width of 8 m), which are arrangedsuccessively in axial direction. Then each of these segments consists ofparts extending over the width of the segment (tear-off blade 15, holder16, support 18), which are each moved up and down by two lateralpiston-cylinder units 19, 20 and wherein the tilting motion of thetear-off blade 15 is performed by two lateral piston-cylinder units 21,22 fastened to the lower part of the support 8.

As soon as the bearing load of the winding rolls 4 exceeds a certainvalue during winding, the frontal sealing elements 12 are swung into thecylinder bed 3 and moved axially against the frontal sides of windingrolls 4. The air box 8 is swung upwards, so that the lower wedge betweenthe support cylinders 1, 2 is sealed off and the sealing elements 12 cancome to rest on its upper limiting surface. The elements 12 seal off theair exit slot 11 outside of the winding roll area. By introducingcompressed air into the air box 8, under the winding rolls 4 asuperatmospheric pressure is created, which reduces the bearing load tothe desired value. The compressed air leaves through the air exit slot11, while all parts of the cutting knife 14, including the tear-offblade 15, are lowered in the air box 8. This position is shown in FIG.2.

After the winding operation is concluded, the compressed air is turnedoff, the frontal sealing elements 12 are swung out of the cylinder bed 3and the tear-off blade 15 of the cutting knife 14 is moved into cuttingposition, as shown in FIG. 3. For this purpose first compressed air isintroduced into the cylinders 21, this prestressing the pistons 22. Atilting motion of the holder 16 is not possible yet, because a lateralmovement of the wheels 26 in the direction of support cylinder 2 isprevented by the guide rails. Subsequently the piston-cylinder units 19,20 move the tear-off blade 15 upwards. As soon as the wheels 26 haveleft the upper part of air box 8, they are deflected against the supportcylinder 2. Thus, during the upward motion of the tear-off blade 15 atilting motion in the direction of support cylinder 1 takes place,without the need to guide the piston-cylinder units 21, 22.

The height of support 18, the width of holder 16 and the stroke ofpiston 22 are selected so that when the piston rods 19 move upwards, thetear-off blade 15 positions itself exactly in its cutting position inthe cylinder bed 3, at a short distance from the web-looped supportcylinder 1. Subsequently the fully wound rolls 4 are pushed off over thesupport cylinder 2 which is not looped, and thereby the web 5 is torn bythe tear-off blade 15. The so-created new web beginning is held onsupport cylinder 1, e.g. by suction. Subsequently the tear-off blade 15is again lowered into the air box 8. For this purpose, first thetear-off blade 15 with the piston-cylinder units 19, 20 is set in anapproximately vertical position, after that the piston-cylinder units19, 20 move the support 18 with all its mounted parts downwards, untilthe tear-off blade 15 is in the air box 8. After a set of new windingcores 6 have been inserted in the cylinder bed 3 and the new webbeginnings have been fastened thereto, the support cylinders 1, 2 areagain set in rotation and the winding operation is restarted.

We claim:
 1. A winding machine, comprising:two support cylindersextending over a width of the machine and defining an upwardly wideningupper wedge-section gap opening upwardly at a bed formed by saidcylinders and on which a roll wound from a web of material rests, saidweb being partially looped about one of said support cylinders, saidsupport cylinders further defining an upwardly converging lowerwedge-section gap communicating with said upper gap; an air box receivedin said lower wedge-section gap and having flanks sealingly engagingsaid support cylinders, said air box having a chamber, a compressed airsupply line connected to said chamber for supplying compressed airthereto, and an upwardly open air exit slot extending over said machinewidth for pressurizing said upper gap and relieving force with whichsaid roll rests on said cylinders; a tear-off blade received in said airbox and raisable through said slot out of said air box into a cuttingposition at said cylinder bed for cutting said web upon completion ofsaid roll, thereby allowing removal of said roll from said bed, saidblade being fully retractable into said air box through said slot; asupport in said air box carrying said blade and raisable and lowerablein said air box; and actuating means in said air box operativelyconnected to said support for selectively displacing said support toretract said blade and displace said blade into said cutting position.2. The winding machine defined in claim 1, further comprising a holderarticulated to said blade and to said support for canting said bladetoward said one of said cylinders upon raising of said blade from saidair box through said slot.
 3. The winding machine defined in claim 2wherein said holder is a two-part lever having a side turned away fromsaid blade formed with a piston-and-cylinder unit fastened to saidsupport.
 4. The winding machine defined in claim 3 wherein saidpiston-and-cylinder unit is linked to a lever articulated to said holderat a link point slightly offset toward the other of said cylinders uponretraction of said unit.
 5. The winding machine defined in claim 2,further comprising a wheel mounted freely rotatably on an end of saidholder opposite said blade.
 6. The winding machine defined in claim 5,further comprising a guide formed in said air box for said wheel.
 7. Thewinding machine defined in claim 1 wherein said actuating means is apiston-and-cylinder unit having at least a piston rod located insidesaid air box.